-지만 — but (clear contrast)
비싸*지만 좋아요.* — It's expensive but good. Works with any tense: 먹었*지만 배고파요.*
-는데 / -(으)ㄴ데 — softer "but", or giving background
- Action verbs and 있다/없다: -는데 (가는데, 먹는데, 있는데)
- Descriptive verbs: -(으)ㄴ데 (비싼데, 좋은데)
- Nouns: -인데 (학생인데)
- Past: -았/었는데 (갔는데)
Background: 배가 고픈*데 밥 먹으러 갈까요?* — I'm hungry; shall we go eat? Contrast: 한국어는 어려운*데 재미있어요.* — Korean is hard, but fun. At the end of a sentence, it softens or implies more: 좋은데요? — It's (surprisingly) good!